Alcohol is known to affect developing tissues, evidenced by the fetal alcohol syndrome, but the molecular mechanisms of such effects are not known. In this study we have used sand dollar eggs to investigate the effects of ethanol on early stages of cell division. Video-enhanced microscopy was used to study the effects of ethanol on mitosis of sand dollar eggs. Our preliminary study showed that in the presence of low concentrations (30-50 mM) of ethanol, the immediate effects included paralysis of sperm tail motility and distortion of the embryo fertilization envelope. Later effects included disruption of cytoplasmic organization and inhibition of mitosis. The data suggest that ethanol may affect the ability of a cell to progress through the cell cycle and mitosis. Similar results were obtained when micromolar calcium chloride was injected into these eggs. The studies on sand dollar eggs could provide an experimental model for investigating the mechanism of the effects of ethanol on the early stages of development. The intracellular calcium concentration in clonal AtT-20/D16 mouse anterior pituitary tumor cells and in rat hepatocytes was measured with the fluorescent calcium indicator Quin 2. A fourfold increase in intracellular calcium was observed in 50 mM KC1 Krebs solution compared to 5 mM KC1 normal Krebs solution. In normal Krebs solution, ethanol (30 mM) caused a 10% increase in intracellular calcium concentration in rat hepatocytes, but under these conditions AtT-20/D16 cells showed no significant change. These observations suggest that the effects of ethanol on cellular calcium metabolism may vary in different cell types.